- Selective deacetylation using iodine-methanol reagent in fully acetylated nucleosides
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Selective deprotection of primary acetyl ester in nucleosides and carbohydrates using 1% iodine-methanol solution (w/v) was described and the mechanism was also discussed.
- Ren, Bo,Cai, Li,Zhang, Liang-Ren,Yang, Zhen-Jun,Zhang, Li-He
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- Synthesis and enzymic hydrolysis of acylated adenosine derivatives
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Various derivatives of adenosine were prepared by acylation of adenosine (6-amino-9-(β-D-ribofuranosyl)purine (1) with different molar equivalents of acetic anhydride and/or pivaloyl chloride in pyridine. Compounds 6-acetylamino-9-[(2,3,5-tri-O-acetyl)-β-D-ribofuranosyl]purine (3), 6-amino-9-[(2,3,5-tri-O-acetyl)-β-D-ribofuranosyl]purine (4), and 6-pivaloylamino-9-[(2,3,5-tri-O-pivaloyl)-β-D-ribofuranosyl]purine (5) were subsequently submitted to hydrolysis catalyzed by a number of hydrolytic enzymes. Regioselective enzymic deacetylation at the primary hydroxyl group of 3 and 4 with butyrylcholinesterase (BChE) produced 6-acetylamino-9-[(2,3-di-O- acetyl)-β-D-ribofuranosyl]purine (9) and 6-amino-9-[(2,3-di-O-acetyl- β-D-ribofuranosyl]purine (10), respectively. All structures were established by 1H and 13C NMR spectroscopies.
- Car,Petrovic,Tomic
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- ENZYMATIC REGIOSELECTIVE DEACYLATION OF 2',3',5'-TRI-O-ACYLRIBONUCLEOSIDES: ENZYMATIC SYNTHESIS OF 2'3'-DI-O-ACYLRIBONUCLEOSIDES
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A simple and convenient method was developed for the synthesis of 2',3'-di-O-acetylribonucleoside in good yields by the regioselective enzymatic hydrolysis at the primary hydroxyl group of 2',3',5'-tri-O-acetylribonucleosides.
- Singh, Haribansh K.,Cote, Gregory L.,Sikorski, R. Steven
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- Immobilization of neutral protease from Bacillus subtilis for regioselective hydrolysis of acetylated nucleosides: Application to capecitabine synthesis
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This paper describes the immobilization of the neutral protease from Bacillus subtilis and its application in the regioselective hydrolysis of acetylated nucleosides, including building blocks useful for the preparation of anticancer products. Regarding the immobilization study, different results have been obtained depending on the immobilization procedure. Epoxy hydrophobic carriers gave a poorly stable derivative that released almost 50% of the immobilized protein under the required reaction conditions. On the contrary, covalent immobilization on a differently activated hydrophilic carrier (agarose) resulted in very stable enzyme derivatives. In an attempt to explain the obtained enzyme immobilization results, the hypothetical localization of lysines on the enzyme surface was predicted in a 3D structure model of B. subtilis protease N built in silico by using the structure of Staphylococcus aureus metalloproteinase as the template. The immobilized enzyme shown a high regioselectivity in the hydrolysis of different peracetylated nucleosides. A stable enzyme derivative was obtained and successfully used in the development of efficient preparative bioprocesses for the hydrolysis of acetylated nucleosides, giving new intermediates for the synthesis of capecitabine in high yield.
- Bavaro, Teodora,Cattaneo, Giulia,Serra, Immacolata,Benucci, Ilaria,Pregnolato, Massimo,Terreni, Marco
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- Discovery of Leucyladenylate Sulfamates as Novel Leucyl-tRNA Synthetase (LRS)-Targeted Mammalian Target of Rapamycin Complex 1 (mTORC1) Inhibitors
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Recent studies indicate that LRS may act as a leucine sensor for the mTORC1 pathway, potentially providing an alternative strategy to overcome rapamycin resistance in cancer treatments. In this study, we developed leucyladenylate sulfamate derivatives as LRS-targeted mTORC1 inhibitors. Compound 18 selectively inhibited LRS-mediated mTORC1 activation and exerted specific cytotoxicity against colon cancer cells with a hyperactive mTORC1, suggesting that 18 may offer a novel treatment option for human colorectal cancer.
- Yoon, Suyoung,Kim, Jong Hyun,Kim, Sung-Eun,Kim, Changhoon,Tran, Phuong-Thao,Ann, Jihyae,Koh, Yura,Jang, Jayun,Kim, Sungmin,Moon, Hee-Sun,Kim, Won Kyung,Lee, Sangkook,Lee, Jiyoun,Kim, Sunghoon,Lee, Jeewoo
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p. 10322 - 10328
(2016/12/07)
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- Stereoselective formation of a P-P bond in the reaction of 2-alkoxy-2-thio-1,3,2-oxathiaphospholanes with O,O-dialkyl H-phosphonates and H-thiophosphonates
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A new method for the formation of organohypophosphates containing a P-P bond under mild conditions, based on the DBU-assisted reaction of 2-alkoxy-2-thio-1,3,2-oxathiaphospholanes with O,O-dialkyl H-phosphonates or H-thiophosphonates, has been elaborated. The resulting triesters of P 1-thio- and P1,P2-dithiohypophosphoric acids, respectively, having O-methyl or O-ethyl groups, can be selectively dealkylated to form the corresponding di- or monoesters. Appropriately protected 2′-deoxyguanosine-3′-O-(2-thio-1,3,2-oxathiaphospholane) was converted into the corresponding P1-thio- and P1,P 2-dithiohypophosphate esters in a highly stereoselective manner (98%+ and 90%+, respectively).
- Blaziak, Damian,Guga, Piotr,Jagiello, Agata,Korczynski, Dariusz,MacIaszek, Anna,Nowicka, Anna,Pietkiewicz, Aleksandra,Stec, Wojciech J.
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supporting information; experimental part
p. 5505 - 5510
(2011/02/18)
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- A versatile synthesis of 5'-fenctionalized nucleosides through regioselective enzymatic hydrolysis of their peracetylated precursors
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We describe a chemo-enzymatic synthesis of modified nucleosides through lipase-catalyzed hydrolysis of their peracetylated precursors. It was found from screening of a large number of substrates that these enzymesregioselectivities were affected by the sugar and the nucleobase structures. By selecting the best enzyme for each substrate in terms of activity and regioselectivity, we prepared a small library of differently monodeprotecled purine and pyrimidine nucleosides useful as intermediates for the synthesis of high-value nucleosides and mononucleotides. By this approach, the chemo-enzymatic preparation of doxifluridine (14) and uridine 5'-monophosphate (5'-UMP, 15) from peracetylated uridine 1 was carried out. Elimination of many of the processing stages associated with existing methods was achieved, and higher yields and products of increased purity were generated. Wiley-VCH Verlag GmbH & Co. KGaA.
- Bavaro, Teodora,Rocchietti, Silvia,Ubiali,Filice, Marco,Terreni, Marco,Pregnolato, Massimo
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experimental part
p. 1967 - 1975
(2009/09/08)
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- The action of adenosine deaminase (E.C. 3.5.4.4.) on adenosine and deoxyadenosine acetates: The crucial role of the 5'-hydroxy group for the enzyme activity
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From adenosine 1, 2'-deoxyadenosine 3 and 3'-deoxyadenosine 5 all the acetates were prepared by lipase-catalyzed reactions. Only the acetates with free 5'-hydroxy group were deaminated by adenosine deaminase (ADA), confirming the crucial role of 5'-OH for the enzyme activity. (C) 2000 Elsevier Science Ltd.
- Ciuffreda, Pierangela,Casati, Silvana,Santaniello, Enzo
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p. 3239 - 3243
(2007/10/03)
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